Use non-$(match)-changing matching function where applicable

FullTextMatch is only useful for places where language mandates
$(match) namespace to be populated.
Move opt_dry_run class definition from CheckOpts

CheckOpts is oguht to parse options, but delay execution until
later time (EvalContext is not supposed to be available so early
in runtime). The only use of EvalContext was in setting up
'opt_dry_run' class, which we set instead later using DONTDO
global variable.
Store dumminess of lock in lock itself
Move IGNORELOCK to EvalContext